package com.zyx.nettypro.netty.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * @author Yaxi.Zhang
 * @since 2021/9/23 14:15
 */
public class MyServer {
    public static void main(String[] args) {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(workerGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            pipeline
                                    // 因为基于http协议, 使用http的编码和解码器
                                    .addLast(new HttpServerCodec())
                                    // 以块方式写, 添加ChunkedWriteHandler处理器
                                    .addLast(new ChunkedWriteHandler())
                                    /*
                                        说明
                                            1. http数据在传输过程中是分段, HttpObjectAggregator, 就是可以将多个段聚合
                                            2. 这就就是为什么, 当浏览器发送大量数据时, 就会发出多次http请求
                                     */
                                    .addLast(new HttpObjectAggregator(1 << 13))
                                    /*
                                        说明
                                            1. 对应websocket, 它的数据是以 帧(frame) 形式传递
                                            2. 可以看到 WebSocketFrame 下面有六个子类
                                            3. 浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                                            4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议, 保持长连接
                                            5. 是通过一个 状态码 101
                                     */
                                    .addLast(new WebSocketServerProtocolHandler("/hello"))
                                    .addLast(new MyTextWebSocketFrameHandler());
                        }
                    });

            ChannelFuture cf = bootstrap.bind(7000).sync();
            cf.channel().closeFuture().sync();

        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}
